Heat exchangers with separate fluid flow paths are often used to transfer heat from one medium to another without intermixing of the two fluids. In many applications it is vital to avoid any intermixing—to prevent food products becoming contaminated with coolant in heat exchangers used in food processing plant or dairy pasteurisers for example.
For one reason or another, heat exchangers can sometimes have small leaks which may go undetected, perhaps due to minute manufacturing detects or corrosion. It is therefore necessary to provide a simple and reliable way of detecting leaks, whether it be a newly manufactured heat exchanger or one which is being returned to service after a period of use or following a maintenance procedure for example.